This invention relates generally to the care of human patients, and more specifically to a method and apparatus for performing endotracheal suctioning of a patient who is connected to a respirator machine.
Ventilation of patients by connecting them to a respirator is a widespread practice to aid in their breathing when critically ill, such as during or immediately following an operation. A typical respirator provides a breathing gas for the patient having a high level of oxygen in one tube and receives back in another tube the gases exhausted by the lungs of the patient. These two tubes are joined together at a manifold position that is as close to the point of entry to the patient as possible. A single additional tube positioned into the trachea of the patient, either directly or through the nose or mouth, is connected to the manifold. A principal goal of such a ventilation technique is to maintain a high level of blood oxygenation in the patient without the heart and lungs having to work excessively hard.
A patient so connected to a respirator requires periodic removal of fluid from the trachea. The present technique as widely practiced in hospitals is to disconnect the respirator hoses from the patient, and then to insert through the tracheal tube a separate, small-diameter suctioning tube which is used to remove the fluids from the trachea. During this periodic process, some temporary breathing assistance is provided, but not of the quality or quantity as provided by the respirator. This interruption necessarily results in the oxygen level of the blood to decrease, and for the heart and lungs to have to work harder, a problem with many critically ill patients. Much has been written about the solution to this problem, typical suggestions being to hyperinflate the lungs before and/or after the suctioning process, and varying the parameters of the suctioning operation, including the size of the suctioning tube, the suctioning pressure, its duration, etc. But none of these techniques result in maintaining the same level of breathing assistance as when the patient's connection to the respirator is uninterrupted.
The use of positive end expiratory pressure (PEEP) has gained wide popularity in the management of the respiratory status of critically ill patients. Generally, this known technique maintains through an appropriate respirator a slightly positive gaseous pressure to the patient at all times. The basic advantage of this technique is that it allows a lower concentration of oxygen to be provided to the patient in order to maintain an adequate level of blood oxygenation. It is thought that this is due to the fact that the positive pressure maintains a larger number of the patient's lung alveoli open during the respiratory support, thereby increasing the effective lung area of ventilation and decreasing ventilation/perfusion defects. Although there is some controversy as to the effect of interrupting such a positive pressure for various nursing maneuvers such as suctioning, changing tubing, etc., empirical data tends to suggest that the interruption of the positive pressure leads to an immediate effect in a sudden collapse of lung alveoli. This data also suggests that it takes a substantial amount of time after such an interruption for the positive pressure to restore the lung alveoli to their open state.
Therefore, it is a primary object of the present invention to provide a method and apparatus for endotracheal suctioning of a patient which eliminates the foregoing disadvantages associated with existing interruptions of respiratory support to the patient.